KR20040026150A - Radiant electric heater incorporating a temperature sensor assembly - Google Patents

Abstract

A radiant electric heater (2) is arranged for location underneath and against a cooking plate (12) and incorporates a heating element (14) spaced from the cooking plate and a temperature sensor assembly (26). The temperature sensor assembly (26) comprises a beam (28) of ceramic material provided within the heater and extending at least partially across the heater over the at least one heating element (14). The beam (28) has a substantially planar upper surface (32) arranged to face the cooking plate (12), in contact with the cooking plate or in close proximity to it, and an under surface (34) arranged for exposure to direct radiation from the heating element (14). Provided on the planar upper surface (32) is an electrical component (36), such as of film or foil form, having an electrical parameter which changes as a function of temperature of the cooking plate.

Description

RADIANT ELECTRIC HEATER INCORPORATING A TEMPERATURE SENSOR ASSEMBLY}

Radial electric heaters are very well known and in particular are provided in contact with or below the cooking plate of glass-ceramic material, and typically use electrical or electromechanical thermal sensors to limit the maximum temperature of the upper surface of the cooking plate. With a heater.

In current technology, the temperature sensor detector is located in the space between the heating element and the bottom of the cooking plate. The disadvantage of such an arrangement is that the temperature obtained by the temperature detector does not accurately reflect the temperature of the upper surface of the cooking plate as it is affected by direct radiation from the heating element. The detection temperature is usually around 100-200 ° C above the corresponding temperature of the top temperature of the cooking plate. As a result, there are two temperature variations between the sensor detector and the upper surface of the cooking plate, that is, one temperature change between the sensor detector and the cooking plate and another temperature change between the bottom of the cooking plate and its upper surface. The temperature gradient can be varied by varying the heat and heater temperature profile applied by the selected cooking bezel located on the top surface of the cooking plate at the heater power density. The cooking bezel is influenced by the upper surface temperature of the cooking plate.

The temperature sensor used in such a heater is arranged to reduce the energy of the heating element at a preset temperature value. The preset temperature value is determined by an abnormal loading condition (eg : Uncooked bezel; boiling dry; offset cooking bezel on cooking plate; cooking bezel with concave base to be boiled). Repeated switching of the heating element under the latter condition is undesirable because of the increased boiling time.

When an electronic temperature sensor is employed, the undesirable switching possibilities of the heating elements occurring are clearly reduced by incorporating an intelligent control profile within the 'quick boiling' control settings provided. This requires the use of costly intelligent, usually digital, microprocessor controllers.

The tolerance range of the preset temperature value of the temperature sensor is critical by mixing the aforementioned variables. Electromechanical temperature sensors typically have tolerances on the order of 50-60 ° C due to material, design and manufacturing limitations. Currently available electronic temperature sensors show a lower tolerance range, but the devices are more expensive than electromechanical temperature control systems with the control circuits they require.

In addition, the above-described variables and temperature gradients make the electronic temperature sensor only useful when used as a maximum temperature control device, so that it is only used to deenergy the thermal element to a predetermined temperature value. The electronic temperature sensor cannot support the cooking plate according to the required cooking task cycle, which includes a 'closed loop' controlled temperature solving.

Current temperature control systems for cooking apparatus with glass-ceramic cooking plates are essentially 'open loops'.

The temperature control system can take into account changes in cooking bezel material and shape variables, cooking bezel mass, mass and heat capacity of the food in the cooking bezel, and most importantly, temperature gradients such as heating and cooking bezel of the contents as the water evaporates. none. Constant adjustment of the heater is required for the user, especially at low settings.

In addition, the maximum operating temperature for glass-ceramic cooking plates is expected to increase to about 40 ° C. in the near future as a result of material and process evolution. The purpose of the temperature increase is to reduce the likelihood of de-energization of the heater during the boiling-fuel state cycle by providing the possibility of reaching a higher temperature prior to switching of the heating element.

Currently available temperature sensors must be further developed for resistance due to the higher maximum temperatures encountered during service due to the limitations imposed by the sensor elements and enclosure materials present. This makes the cost for the sensor system further increased.

The present invention relates to a radiant electric heater in combination with a temperature sensor assembly wherein the heater is disposed below a cooking plate such as glass-ceramic. In particular, the invention relates to such a heater provided with a sensor element having an electrical parameter that changes with a temperature function.

1 is a plan view of one embodiment of a radiant electric heater according to the present invention provided with an embodiment of a temperature sensor jolev and an electrical control device shown in schematic form.

2 is a cross-sectional view of the heater of FIG. 1 under a cooking plate.

3 and 4 are perspective views from different angles of the temperature sensor assembly formed in the heater of FIG. 1.

5 is a detailed view of an optional mounting arrangement for the temperature sensor assembly in the heater of FIG. 1.

6 is a cross-sectional view of another embodiment of a radiant electric heater according to the present invention in which a temperature sensor assembly is coupled.

7 and 8 are perspective views from different angles of the temperature sensor assembly formed in the heater of FIG. 6.

9 is a top view of a radiant electric heater in accordance with the present invention in which a temperature sensor assembly is formed and has a dual heating zone.

10 is a schematic diagram of an embodiment of a temperature control device used as the radiant electric heater of the present invention.

It is an object of the present invention to overcome or minimize one or more of the above mentioned problems. According to the invention, there is provided a radiant electric heater in which the heater is arranged below and opposite the cooking plate and is provided with a heating element and a temperature sensor spaced from the cooking plate, the temperature sensor assembly being provided in the heater and onto the heating element. And a beam of ceramic material extending partially across.

The beam has a flat top surface disposed below the surface arranged to be exposed to direct radiation from the heating element and facing the cooking plate. The flat top surface is provided with an electrical element having electrical parameters that change as a function of temperature of the cooking plate. The temperature sensor assembly may be located in the central region of the heater. Optionally, the temperature sensor assembly may be secured to an end region of the heater around the heater.

One or more end regions of the beam may extend outside the heater. In this case, the beam may be fixed at one end region with the heater by a bracket which receives one end region of the beam and is fixed to an outer region of the heater. The bracket may be a ceramic or plastic material.

Optionally, the bib can be secured at one end region to the heater passing through a hole in the peripheral wall of the heater. The peripheral wall may comprise a rigid material, such as bound vermiculite. The terminal block can be raised at or near one end region of the beam. The beam may be supported by a spring that deflects towards the cooking plate.

Electrical elements having electrical parameters that change with the temperature function of the cooking plate may be employed to be electrically connected by electrical leads to the electronic control unit of the heater. The electronic control device may be arranged to receive an input signal from each electrical element on or on the upper surface of the beam and also from the manual control switch device. Each global element or input signal therefrom may be processed by a fail-safe circuit having a fixed initial value for temperature and each heating circuit may be de-energized to a temperature above the fixed initial value for temperature. Can be arranged.

The input signal from the manual control switch device and the input signal from each electrical element can be processed by an analog or digital signal processing circuit in contact with the switch means for controlling the energization of each heating element.

The signal processing circuit is arranged to compare the sensed temperature with the position of the manual control switch device and energize or deenergy each heating element depending on whether the sensed temperature is above or below the respective set by the manual control switch device. Can be.

When the signal processing circuit is a digital circuit, it may include a microprocessor in contact with a manual control switch by a digital output driver and in contact with each electrical element by an analog to digital converter.

When the signal processing circuit is an analog circuit, an analog signal for controlling the energyization of each heating element is compared with an input signal from a manual control switch device having an input signal from each electrical element, and proportional to the difference between the two input signals. And signal processing integrated circuits.

The control of the energization of each heating element can be achieved by an output signal tailored to the specific control requirements of the solid state switch device which operates to control the energization of each heating element. Control of each heating element can be achieved in a closed loop method.

The upper surface of the beam is arranged to contact or approach the cooking plate. The upper surface of the substantially flat beam may be arranged to face the cooking plate at a distance no greater than 3.5 mm therefrom. The upper surface of the substantially flat beam may be arranged to face the cooking plate at a distance between there 0.5-3.5 mm or preferably between 0.5-2.0 mm.

Electrical elements having electrical parameters that vary as a function of temperature may be in the form of films or foils. The electrical element in the form of a film or foil may have an electrical conductor in the form of a film or foil extending from them to one end region of the beam which is adapted to be fixed to the heater at its periphery. Electrical elements in the form of films or foils may include electrical resistive elements that vary as a function of temperature. The electrical resistive element may comprise platinum. The electrical element may be in the form of a thick film.

A protective layer such as glass or ceramic can be formed over the electrical element. A layer of heat radiation reflecting material may be formed on the top surface of the beam. The beam may be structurally strengthened by having a T- or H-shaped cross section. The beam may comprise steatite such as alumina or corelite.

A plurality of heating zones with each heating element are formed side by side in the heater, such as concentrically arranged, such that a plurality of corresponding electrical elements are formed on the upper surface of which the beam is substantially flat, with each electrical element located within the corresponding heating zone and accordingly The temperature of the cooking plate in each heating zone can be monitored.

The temperature difference between the plurality of heating zones can be determined by the electrical control device together with the plurality of electrical elements, the curvature of the base of the cooking bezel on the cooking plate or the size of the cooking plate of the cooking plate or the position or arrangement of the cooking bezel on the cooking plate. Can be used to determine.

The radiant electric heater of the present invention is preferred in that temperature-sensing electrical elements or elements, such as, for example, films or foils, on the upper surface of the beam are not directed towards the cooking plate or exposed to direct radiation from the heating element or elements. The beam protects the temperature sensing element or elements from the heating element or elements.

The temperature sensing assembly may be at the bottom of the cooking plate and is thus configured to ensure that the temperature gradient between the temperature sensing assembly and the bottom of the cooking plate is clearly reduced. The increased distance between the heating element or elements and the temperature sensing assembly reduces the direct radiation effect from the heating element or elements on the sensor assembly.

Due to the low temperature difference between the cooking plate and the temperature sensor assembly, the assembly can be made more reliable at the higher maximum temperature of the cooking plate being introduced. An average maximum temperature of 590-630 ° C. is introduced into the glass-ceramic cooking plate compared to the current maximum temperature of 550-590 ° C.

Another advantage of the present invention is that the heater system can be adjusted to a lower cooking plate temperature under free spinning without the unwanted switching of heating elements or elements during the boiling cycle with the cooking bezel. Having a lower cooking plate temperature under free spinning reduces heat loss under that condition. This increases the efficiency of the cooking apparatus.

The improved thermal connection between the temperature sensor assembly and the cooking plate allows the use of low cost electrical control techniques, alleviating the need for specific high temperature excursion profiles applied through software based algorithms programmed with microcontrollers.

Maximum temperature control can be provided through a single preset control point, employing analog or digital technology using low cost integrated circuits and combining temperature limiting and heater energy control. It is also possible to apply closed loop control of the cooking plate temperature by adjusting the heater input energy. The cooking plate temperature can be applied as input to the regulator control system so that a more constant and predictable power control is achieved.

In order to better understand the present invention and to clarify the effect to be performed, the following drawings are attached.

1 and 2, the radiant electric heater 2 has a metal plate-shaped support 4 and bound vermiculite having a base 6 of thermal and electrical insulating material, such as thermal and electrical insulating material of micropores therein; A peripheral wall 8 which is the same thermal and electrical insulating material. The peripheral wall 8 is arranged in contact with the bottom 10 of the cooking plate 12, which is a glass-ceramic material.

One or more radiative electroheating elements 14 are supported relative to the base 6 in the heater. The heating element or elements 14 may comprise any of the known types of elements, such as lamps of wires, ribbons, foils or elements or combinations thereof. In particular, the heating element or elements 14 may comprise one or more corrugated ribbon heating elements supported laterally on the base.

One or more heating elements 14 are connected by a terminal block 16 via an electronic control device 20 in which a control switch device is manually operated. The control switch device 22 has a rotatable knob arranged to provide selected heating control for one or more heating elements 14 in the heater 2. The cooking plate 12 is arranged to receive the cooking bezel 24 on its upper surface 25.

The temperature sensor assembly 26 shown in detail in FIGS. 3 and 4 is formed in the heater 2. The temperature sensor assembly 26 supports a beam 28 of ceramic material which is supported at one end region 30 around the heater and partially extends across the heater above and is spaced apart from at least one heating element 14. Include.

The beam 28 has a substantially flat top surface 320 disposed to face the bottom 10 of the cooking plate 12 proximate or in contact therewith.The top surface 32 of the beam 28 is 0.5 mm. It is preferably spaced apart from the lower portion 10 of the low cooking plate 12 but not more than 3.5 mm and particularly less than 2.0 mm.

The beam 28 suitably contains steatite, alumina or cordialite ceramic material and is structurally strengthened to minimize the risk of bending or breaking. The structural reinforcement is suitably achieved by providing a beam 28 of H-shaped cross section as shown in FIG. 3 or of a T-shaped cross section shown in FIG. 7 described below.

Beam 28 has a lower surface 34 disposed for exposure to radiation directly from one or more heating elements 14. The lower surface 34 of the beam may be formed with a layer of thermal radiation reflecting material, such as silver, to minimize the absorption of heat by the beam 28 from the direct radiation of one or more heating elements 14.

The substantially flat upper surface 32 of the beam 26 is formed thereon with one or more electrical elements 36 in the form of a film or foil having electrical parameters that change with the temperature warm water of the cooking plate 12. The one or more electrical elements 36 have an electrical conductor 38 in the form of a film or foil that extends from them to the terminal land 40 in the end region 30 of the beam 28.

The one or more electrical elements 36 in the form of films or foils preferably have one or more electrical resistive elements whose electrical resistance changes as a function of temperature. The one or more electrical resistive elements suitably comprise platinum. The one or more electrical elements 36 and leads 38 are in the form of thick films suitably formed by screen printing or firing onto the upper surface 32 of the beam 28.

A protective layer 42, such as glass or ceramic, may be formed over one or more electrical elements 36 of the film or foil. The beam 28 is arranged to extend through the peripheral wall 8 of the dish-shaped support means 4 of the heater 2 and the hole in the rim so that the end region 30 of the beam 28 is the heater 2. Position it outside of

The beam 28 is fixed to the rim of the dish-shaped support means 4 by a threaded fastener 46 passing through the hole 48 in the bracket 44 and in the end region 30 of the beam 28. The metal, ceramic or plastics material to be fixed is fixed to the heater 2 by means of a suitable bracket 44.

If the bracket 44 is a plastic material, the beam 28 can have its end region 30 inserted and cast into the bracket 44, and if the bracket 44 is a ceramic material, the dovetail interconnection between them It may be fixed to the end region 30 of the beam 28 to be formed.

The terminal block 50 is connected to the terminal land 40 of the end region 30 of the beam 28 by a lead wire 52 and fixed to the bracket 44 as appropriate. Since the end region 30 of the beam is located outside the heater, the lead wire 52 need not have a high temperature resistance and may include a material such as copper. If the bracket 44 includes a plastic or ceramic material, the terminal block 50 may be integrally formed therewith. The temperature sensor assembly 26 is electrically connected to the electrical control device 20 by an electrical lead 54.

As shown in FIG. 5, instead of the bracket 44 formed to fix the beam 28 to the heater 2 at its end region 30, the beam 28 is complementary in the circumferential wall 8 of the heater. It has an end region 30 fixed to the hole 56 of. The peripheral wall 8 of particularly hard bound vermiculite can be arranged to securely fix the beam to the heater 2.

6,7 and 8 show an alternative embodiment similar to FIGS. 1-4 except that the T-shaped cross-sectioned beam 28 is spring mounted relative to the lower portion 10 of the cooking plate 12. . By mounting the spring between the lower surface 10 of the cooking plate 12 and the upper surface 32 of the beam 28 while reducing mechanical damage to the temperature sensor assembly 26 or the cooking plate 12 when mechanical shock is applied. Allow contact.

The spring mounting is accomplished by one or more coil springs 58 cooperating between the bottom of the end region 30 of the beam 28 and the end support bracket, which is a metal such as nickel plate steel.

A strut 60 is also formed in the center region of the heater 2, which strut 60 is downward from the beam 28, through a hole formed in the base 6 and the metal plate-shaped support means 4. And a hole formed in the metal bracket 62 fixed to the dish-shaped support means 4. Coil spring 64 is arranged to cooperate between strut 60 and metal bracket 62.

The radiant electric heater 2 constructed in accordance with the present invention has the advantage that the temperature sensor assembly 26 is thermally intimately connected with the cooking plate 12 so that the annual variation between the assembly and the bottom of the cooking plate 12 is minimized. .

One or more temperature-responsive electrical elements 36 in the form of a film or foil on the upper surface 32 of the beam 28 in turn direct radiation from the one or more heating elements 14 by the thickness of the beam 28 and at least one temperature. The reactive electrical element 36 responds primarily to the temperature of the cooking plate 12. This allows a simple electronic control device 20 to be employed.

Bring the temperature sensor assembly 26 close to the cooking plate 12 to increase the distance between the one or more heating elements 14 and the temperature sensor assembly 26 to correlate with the optical properties of the reflective layer on the bottom of the beam 28. Thereby reducing the effect of radiation directly from one or more heating elements 14 on the temperature responsive electrical element 36 of the temperature sensor assembly 26.

Referring to FIG. 9, the radiant electric heater 2 is formed in a similar manner to the heaters of FIGS. 1 and 2 except that multiple heating zones are provided. As shown, heating zones 66 and 68 are provided, although two or more may be considered.

The heating zones 66 and 68 are arranged concentrically and one or more heating elements 14A and 14B are formed respectively. The heating zone 66 is arranged to apply energy alone or together with the heating zone 68.

The temperature sensor assembly 26A is described in detail for the temperature sensor assembly 26 except that two separate temperature responsive electrical elements 36A, 36B in the form of film or foil are formed on the upper surface 32 of the beam 38. Is formed as. Element 36A monitors the temperature of the region of the cooking plate over heating zone 66 and element 36B monitors the temperature of the region of the cooking plate over heating zone 68.

Other temperature changes between the cooking plates 66 and 68 can be monitored by detecting the size of the cooking bezel (such as the cooking bezel shown in FIG. 2) located on the cooking plate above the heater. If the temperature of the cooking plate above the external heating zone 68 is increased compared to above the internal heating zone 66, this means that a small cooking bezel is located above the internal heating zone 66 but has two heating zones 66, 68. Indicates. If it is sensed that both heating zones 66 and 68 are excessively hot, this indicates that the two zones 66 and 68 are energized under the free spinning condition without the cooking bezel.

If the temperature of the cooking plate over the inner region 66 is detected to be higher than on the outer region 68 this indicates that a cooking bezel with a bent base is located on the cooking plate.

10 shows an embodiment of an electronic control device 20 for use in the present invention. The device 20 is arranged to receive an input signal from one or more temperature response elements 36 in the form of a film or foil of the temperature sensor assembly 26 and from the manual control switch device. The input signal from the temperature sensor assembly 26 is processed by a fail-safe circuit 70 having a fixed initial value for temperature such that one or more heating elements 14 are at the fixed initial temperature for temperature. It is arranged to be de-energized by the operation of the main switch 72 as relayed.

The input signal from the manual control switch device 220 and the input signal from the temperature sensor assembly 260 are coupled by a solid state control switch 76 such as a triac to control the energization of one or more heating elements 14. By a signal processing circuit 74 of analog or digital form.

The signal processing circuit 74 compares the temperature sensed by the sensing assembly 26 with the position of the manual control switch device 22 and the sensed temperature is more than regulated by the manual switch device 22 or One or more heating elements 14 are arranged to energize or deenergy, depending on whether

If the processing circuit 74 is a digital circuit, it is suitably configured as a microprocessor which is connected to the digital converter with the temperature sensor assembly 26 in analog and connected with the manual control switch 22 by the digital output driver.

If the processing signal 74 is an analog circuit, the energization of the at least one heating element 14 is effected by comparing the input signal from the temperature sensor assembly with the signal from the manual control switch device and proportional to the difference between the two input signals. It may suitably include an integrated circuit employed for controlling the analog signal processing. The control of the energization of one or more heating elements 14 is by means of an output signal that is tailored to the specific control requirements of the solid state switch 76. Thus, the control of one or more heating elements can be accomplished by known closed loop control methods.

Claims (39)

In a radiant electric heater (2) in which a heating element (14) and a temperature sensor assembly are disposed below the cooking plate and spaced from the cooking plate and are spaced apart from the cooking plate, The temperature sensor assembly comprises a beam 28 of ceramic material formed in the heater 2 and partially extending across the heater over the heating element 14, The beam has a flat top surface 32 arranged to face the cooking plate 12 and a bottom surface 34 arranged to be exposed to direct radiation from the heating element, And an electrical element formed thereon having an electrical parameter whose flat top surface changes with the temperature function of the cooking plate. The radiant electric heater according to claim 1, wherein said temperature sensor assembly (26) is located in the center region of the heater (2). A radiant electric heater according to claim 1, wherein said temperature sensor assembly (26) is fixed at an end region of said heater (2) around said heater. 4. The radiant electric heater according to claim 3, wherein at least one end region of the beam extends out of the heater (2). 5. The radiant electric heater according to claim 4, wherein the beam (28) is fixed at one end region as a heater by a bracket (44) fixedly receiving one end region of the beam, and fixed to an outer region of the heater. . A radiant electric heater according to claim 5, wherein said bracket (44) is selected from metals, ceramics and plastics. 5. The radiant electric heater according to claim 3, wherein the beam is fixed in the end region of the heater by passing through a hole in the peripheral wall of the heater. 10. The radiant electric heater according to claim 7, wherein said peripheral wall (8) comprises a rigid material. 9. The radiant electric heater according to claim 8, wherein said peripheral wall comprises bound vermiculite. 10. The radiant electric heater according to any one of claims 3 to 9, characterized in that the terminal block (50) is formed at or adjacent to one end region of the beam (28). Radial electric heater according to any of the preceding claims, characterized in that the beam (28) is supported by a spring which is deflected towards the cooking plate (12). The electric element 36 according to any one of the preceding claims, wherein the electrical element 36 having electrical parameters varying with the temperature function of the cooking plate 12 is transferred to the electronic control device 20 for the heater 2. Radiated electric heater, characterized in that it is employed to be electrically connected. 13. The electronic control device (20) according to claim 12, wherein the electronic control device (20) is arranged to receive an input signal from each electrical element (36) on the upper surface (32) of the beam (28) and also receive an input signal from the manual control switch device (922). Radiation electric heater, characterized in that arranged to receive. 14. An input signal from each electrical element 36 is processed by a fail-safe circuit 70 having a fixed initial value for temperature and each heating element 14 is said initial value for temperature. Radial electric heater, characterized in that arranged to be de-energized at the above temperature. The analogue according to any one of claims 13 to 14, wherein an input signal from the manual control switch device 22 and an input signal from each electrical element are connected to the switch means for controlling the energization of each heating element 14. Or a digital electric signal processing circuit (74). 16. The signal processing circuit 74 compares the position of the manual control switch device 22 with the sensed temperature and determines whether the detected temperatures are above or below each of which is controlled by the manual control switch device. Radial electric heater, characterized in that it is arranged to energize or deenergy the heating element (14). 17. The microprocessor according to any one of claims 15 or 16, wherein the signal processing circuit 74 comprises a microprocessor connected to each electrical element 36 analog to a digital converter and to a manual control switch device by a digital output driver. Radiation electric heater, characterized in that the digital circuit. 17. The method according to any one of claims 15 or 16, wherein the signal processing circuit 74 controls the de-energization of each heating element 140 in a manner proportional to the difference between the two input signals and from each electrical element 36. And an analog circuit comprising an analog signal processing integrated circuit for comparing the on input signal and the on input signal from the manual control switch device (22). 19. The control according to claim 18, characterized in that the control of the energization of each heating element (14) is made by an output signal that is tailored to the specific control requirements of the solid state switch device (76) operative to control the energization of each heating element. Radiant electric heaters. 20. The radiant electric heater according to claim 13 or 19, characterized in that the control of the at least one heating element (140) is made in a closed loop method. A radiant electric heater according to any of the preceding claims, characterized in that the upper surface of the beam (28) is arranged in contact with the cooking plate (12). 21. The radiant electric heater according to one of the preceding claims, characterized in that the upper surface (32) of the beam (28) is arranged in proximity to the cooking plate. 23. The radiant electric heater according to claim 22, characterized in that the flat upper surface (32) of the beam (28) is arranged to face the cooking plate (12) at a distance of 3.5 mm or less. 25. The radiant electric heater according to claim 23, wherein the flat upper surface (32) of the beam (28) is arranged to face the cooking plate (12) at a distance of 0.5-3.5 mm. 25. The radiant electric heater according to claim 24, wherein the flat upper surface (32) of the beam (28) is arranged to face the cooking plate (12) at a distance of 0.5-2.0 mm. A radiant electric heater according to any of the preceding claims, wherein the electrical element (36) having an electrical parameter that changes as a function of temperature is selected in the form of a film or foil. 27. The radiant electric heater of claim 26, wherein the electrical element (36) has an electrical conductor selected in the form of a film or foil extending into one end region of the beam (28). 28. The radiant electric heater according to claim 26 or 27, characterized in that the electrical element (36) comprises an electrical resistance element and the electrical resistance changes as a function of temperature. 29. The radiant electric heater of claim 28, wherein said electrical resistive element comprises platinum. 30. The radiant electric heater according to claim 26 to 29, characterized in that the electrical element (36) is in the form of a thick film. A radiant electric heater according to any of the preceding claims, wherein a protective layer (42) is formed over the electrical element (36). 32. The radiant electric heater according to claim 31, wherein the protective layer (42) is selected from glass and ceramic. Radiation electric heater according to any of the preceding claims, characterized in that a layer of thermal radiation reflecting material is formed on the lower surface (34) of the beam (28). Radiation electric heater according to any of the preceding claims, characterized in that the beam (28) is structurally strengthened. 35. The radiant electric heater according to claim 34, wherein the beam (28) has a T or H-shaped cross section. A radiant electric heater according to any preceding claim, wherein the material of the beam (28) is selected from steatite, alumina and cordierite. A plurality of heating zones (66, 68) with heating elements (14A, 14B), respectively, are formed side by side in the heater (2) and the corresponding plurality of electrical elements (36A, 36B) are arranged in a beam (i.e. 28. A radiant electric heater, characterized in that the temperature of the cooking plate can be monitored as it is formed on the flat upper surface 32 of 32) and each electrical element lies within a corresponding heating zone. 38. The radiant electric heater according to claim 37, wherein the plurality of heating zones (66,68) are formed concentrically. 39. A means according to any one of claims 37 or 38, wherein means 20 for determining a temperature difference between a plurality of heating zones 66,68 cooperating with a plurality of electrical elements 36A, 36B is provided, which cooking A radiant electric heater, characterized in that it is used to determine the curvature of the base of the cooking bezel 24 on the plate or the size of the cooking bezel on the cooking plate or the position or placement of the cooking bezel on the cooking base.